The test, which didn't appear to be of a banned mid- or long-range ballistic missile that could scuttle negotiations, allows North Korea to show its people it is pushing ahead with weapons development while also reassuring domestic military officials worried that diplomacy with Washington signals weakness.

Separately, the North Korean Foreign Ministry accused Pompeo of playing down the significance of comments by leader Kim Jong Un, who said last week that Washington has until the end of the year to offer mutually acceptable terms for an agreement to salvage the high-stakes nuclear diplomacy. Both the demand for Pompeo's removal from the talks and the weapon test point to North Korea's displeasure with the deadlocked negotiations.

In a statement issued under the name of Kwon Jong Gun, director general of the American Affairs Department at the Foreign Ministry, North Korea accused Pompeo of "talking nonsense" and misrepresenting Kim's comments.